Survivability refers to the ability of a network system to fulfill critical services in a timely manner to end users in the presence of failures and/or attacks.In order to establish a highly survivable system,it is necessary to measure its survivability to evaluate the performance of the system’s services under adverse conditions.According to survivability requirements of large-scale mobile ad-hoc networks(MANETs),we propose a novel model for quantitative evaluation on survivability.The proposed model considers various types of faults and connection states of mobile hosts,and uses the continuous time Markov chain(CTMC) to describe the survivability of MANETs in a precise manner.We introduce the reliability theory to perform quantitative analysis and survivability evaluation of segment-by-segment routing(SSR), multipath-based segment-by-segment routing(MP-SSR),and segment-by-segment-based multipath routing(SS-MPR) in large-scale MANETs.The proposed model can be used to analyze the network performance much more easily than a simulation-based approach.Numerical validation shows that the proposed model can be used to obtain a better evaluation result on the survivability of large-scale MANETs. Survivability refers to the ability of a network system to fulfill critical services in a timely manner to end users in the presence of failures and / or attacks.In order to establish a highly survivable system, it is necessary to measure its survivability to evaluate the performance of the system’s services under adverse conditions. According to survivability requirements of large-scale mobile ad-hoc networks (MANETs), we propose a novel model for quantitative evaluation on survivability. The proposed model considers various types of faults and connection states of mobile hosts , and uses the continuous time Markov chain (CTMC) to describe the survivability of MANETs in a precise way. We introduce the reliability theory to perform quantitative analysis and survivability evaluation of segment-by-segment routing (SSR), multipath-based segment- by-segment routing (MP-SSR), and segment-by-segment-based multipath routing (SS-MPR) in large-scale MANETs.The proposed model can be used to analyze the netwo rk performance much more easily than a simulation-based approach. Numerical validation shows that the proposed model can be used to obtain a better evaluation result on the survivability of large-scale MANETs.